Pipe coupling



FIG. 1 is a front, right, perspective view of a pipe coupling showing our new design;

FIG. 2 is a front elevational view thereof, the opposite rear elevational view being identical thereto; and,

FIG. 3 is a right side elevational view thereof, the left side elevational view, the top plan view, and the bottom plan view being identical thereto.

In the drawings, the broken line showing is to illustrate portions of the article and form no part of the claimed design. 

We claim the ornamental design for a pipe coupling, as shown and described. 